低倍泡沫枪是一种由单人或多人携带操作，可以喷射低倍泡沫混合液灭火的消防枪。
参考答案：对
若命题p的否命题是q，命题q的逆命题是r，则r是p的逆命题的（ ）
A．原命题
B．逆命题
C．否命题
D．逆否命题
It is no longer _________it was 20 years ago, ________it was so poorly equipped. [ ]
A. what; when
B. that; which
C. what; which
D. what; that
